therapy (PDT), the low tissue penetration of light remains a fatal weakness. [1][2][3][4] Relatively, ultrasound (US) with a high tissue-penetration depth has become an important diagnostic tool in clinics. [5] High-intensity focused US can ablate cancer cells in clinical applications through instantaneous heating (65-100°C). [6] Whereas, HIFU cannot eliminate bacteria efficiently under above temperature in a short time without tissue scald. [7] For the SDT, it is desirable to develop a highly efficient sonosensitizer to kill pathogens under mild US (medical imaging grade).At present, the reported sonosensitizer are mainly divided into organic and inorganic categories. [8] Inorganic sonosensitizers, such as TiO 2 NPs, ZnO, Fe 3 O 4 , MnWO x , BaTiO 3, and black phosphorus can generate ROS under US irradiation, but most of them are needed to be decorated with noble metals to improve their SDT efficiency. [9][10][11][12][13][14] In addition, most inorganic nanomaterials cannot be biodegraded, which leads to long-term body retention. [15] Currently, the most widely used organic sonosensitizers in SDT are porphyrins and their derivatives. [16,17] Although most organic sonosensitizers have good biocompatibility, biodegradability, and high ROS production efficiency under US irradiation. [18,19]
Sonodynamic therapy (SDT) with non-invasiveness and high tissue-penetrating ability has attracted widespread interest in treating deep-seated tumors or infections. To enhance the treatment efficacy of SDT, the development of high-efficiency and stable sonosensitizers are still needed. Herein, a defective homojunction porphyrin-based metal-organic framework (MOF) with greatly enhanced sonocatalytic ability is easily prepared and used for SDT of osteomyelitis infected by methicillin-resistant Staphylococcus aureus (MRSA). Acetic acid and benzoic acid are chosen as modulators during the hydrothermal synthesis of porphyrin-based MOF. It is found that the crystal structure of MOF shifts from PCN-222 to PCN-224 as the amount of acetic acid increases. Interestingly, the defective PCN (D-PCN) contains a two-phase homojunction structure of PCN-222/PCN-224. The sonocatalytic reactive oxygen species production presents a volcano-type trend with increased acetic acid, among which D-PCN-2 with more content of PCN-224 has the best sonocatalytic antibacterial ability. The reduced band gap introduced a defect, and type-II homojunction structures of D-PCN-2 improve the separation of the ultrasound-triggered electron hole, which significantly enhances the SDT effect. Through a mixed linker approach, this work develops a new defect-induced homojunction MOF with great performance for SDT of MRSA-infected osteomyelitis.